The Mystery of Chopin's Préludes

Chopin's twenty-four Préludes remain as mysterious today as when they were newly published. What prompted Franz Liszt and others to consider Chopin's Préludes to be compositions in their own right rather than introductions to other works? What did set Chopin's Préludes so drastically apart from their forerunners? What exactly was 'the morbid, the feverish, the repellent' that Schumann heard in Opus 28, in that 'wild motley' of 'strange sketches' and 'ruins'? Why did Liszt and another, anonymous,